A conventional automation system usually has sensors mounted on a rotation shaft or a movement shaft to receive feedback signals pertaining to a rotation speed, a new direction, or a displacement in order to effectuate control. A typical sensing signal sensed with a sensor is usually a voltage signal. To allow the voltage signal to be read by the other digital logical components later, it is usually necessary to convert the voltage signal into a digital pulse signal with an encoding program of an encoder and then convert the digital pulse signal into various control signals with a decoder, a counter, or a frequency counter. Furthermore, the control signals thus generated can be used to detect a rotation speed, a new direction, a location, and an angle.
Conventionally, a rotation angle or a linear displacement is detected with magnetic induction between a magnetic sensing component and a magnetic block. The prior art, such as US20040017187, discloses that a sensor for use in sensing rotation or linear displacement comprises a magnetic block and a magnetic field detecting circuit, and further discloses that an angle and a displacement are determined with sine waves generated from two linear Hall elements (LHE), respectively, and defined by a phase difference of 90 degrees. In addition, to allow the LHE to generate a magnetic field which commands a linear relationship with respective to a position, the prior art further discloses that the magnetic block takes on a shape which is so special as to form a multi-pole magnetic block. However, in the course of its displacement, the multi-pole magnetic block takes a journey which depends on its size, and thus the multi-pole magnetic block is subject to a limit in terms of its unexhausted displacement. Given an installation space of a specific volume, the larger the magnetic block, the lesser the unexhausted displacement. As a result, increasing the volume of a device greatly is the only way to augment the range of motion of the device. Another drawback of the multi-pole magnetic block is that it is confronted with strict technical requirements of magnetization, thereby leading to high manufacturing costs of the multi-pole magnetic block.
On the flip side, the aforesaid magnetic induction between the magnetic sensing component and the magnetic block will not occur unless a signal is generated with a Hall switch. The Hall switch must have a built-in Smith triggering delaying circuit for eliminating jitter which might otherwise occur to digital signal conversion, thereby incurring costs.